SEO is an internet marketing technique wherein we do on-page & off-page optimization to boost traffic to a website.Whereas, Search Engine Marketing is where you do ad promotion & marketing using google adwords e.g the ads you see on any website when you visit are promoted ads powered by google adwords, however, there are third party ad platforms also available.Together, SEO + SEM + SMM (Social Media Marketing) are the basis of a digital marketing campaign.

The difference between SEO and SEM is simply that Search Engine Optimization is part of Search engine marketing or Search marketing as it is widely known. Both processes aim in increasing visibility in search engines. SEO is about optimizing the web property to get better rankings in the search results while SEM goes beyond SEO. It involves other methods as well which can get you more search engine visitors like PPC advertising.